Regional variation in adipose tissue metabolism of severely obese premenopausal women.

Lipolytic and lipoprotein lipase (LPL) activities were studied in isolated human adipocytes obtained from two intraabdominal depots (round ligament and omental) and from the subcutaneous abdominal region of nine severely obese premenopausal women (with body mass indices ranging from 37 to 51 kg/m2), aged 36 +/- 3 yr, undergoing gastrointestinal surgery. Both fat cell weight and LPL activity were significantly greater in round ligament adipose cells than in subcutaneous abdominal or in omental adipocytes (P < 0.05). The antilipolytic effect of insulin and the sensitivity to this hormone were also higher in round ligament adipose cells than in omental adipocytes (P < 0.05). Although epinephrine initiated a similar biphasic profile of response in all cell types, the catecholamine promoted a weaker inhibition of lipolysis in omental adipocytes than in subcutaneous abdominal adipose cells (P < 0.05). In addition, a lack of regional variation was found in the maximal antilipolysis initiated by UK 14304 and the alpha 2-adrenoceptors was higher in both subcutaneous abdominal and round ligament fat cells than in omental adipocytes. Moreover, the maximal lipolytic response to isoproterenol or to agents acting at post-receptor levels was not different among fat depots. Finally, a lower beta-adrenergic lipolytic sensitivity associated with a reduced beta-adrenoceptor density was observed in round ligament as compared to omental adipose cells. These data suggest that in massively obese premenopausal women, omental and round ligament adipose tissues show distinct metabolic properties that may contribute to limit the impact of intraabdominal obesity.